1. Field of the Invention
The present invention relates to a technology for embedding information in image data. More specifically, the invention relates to a technology for embedding information regardless of the characteristic of the image data.
2. Description of the Related Art
Invisible information, for example, watermarks, are sometimes embedded in digital data and/or when printing images. A watermark is embedded to prevent forgery or illegal use of data or images. The watermark can be embedded in an image by changing or adjusting a gray value of an image area where the information is to be embedded.
Japanese Patent Application Laid-open No. 2005-117154 discloses a technique in which an embedding algorithm is used to analyze an image in which information is to be embedded, and detect an area where information can be embedded and an area where information cannot be embedded, and information indicating that information is not embedded is embedded in the area where information cannot be embedded.
In the conventional art, however, depending on the characteristics of images, information cannot be embedded in some images.